I appreciate the tweak to animation speed (much more tolerable now) and the list view in Calendar, but it's not as mind blowing as I was hoping for. I have a 5, so I didn't really see the crashes that plagued many 5s devices (although I did have 2 between 7.0 release and now). It made my iPad 3rd gen a little better, but I really didn't have that many issues on it (I had upgraded to iOS 7 and set it up as New).
I did have to eventually set up both devices as New on iOS 7.1. I did the OTA upgrades when it came out, but I ran into issues with wifi connectivity (oddly, the 2.4GHz spectrum and not the 5GHz issues that others have reported) and quirkiness (Mail seemed to take forever to sync, open, switch folders, etc.). But after setting up as New, both devices are performing well, and I don't have any unusual battery drain that often comes with updates. Overall, pretty positive (although it would have been a wonderful gift if Apple had included a quick reply to iMessage right in notification center).